Right, a world allocation fund and world bond fund mix seems like the way to construct a core these days, whether one indexes or tries to outperform.  There aren't that many world bond funds around though.

 The US is still the place with some of the least political corruption and most transparent and liquid markets so US funds aren't a bad way to go.  In any cases, many US fund are now holding a sizable percentage of international stocks, never mind the international exposure one gets via US corporations and their international operations.